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1Author    Norbert Kuhn, Martin Grathwohl, Christiane Nachtigal, Manfred SteimannRequires cookie*
 Title    2.3-Dihydro-2-methoxyethylimino-l,3-dimethylimidazol -ein neuer hemilabil koordinierender Chelatligand [1] 2.3-Dihydro-2-methoxyethylimino-\ ,3-dimethylimidazole -a Novel Hemilabile Coordinating Chelate Ligand [1]  
 Abstract    The bifunctional 2,3-dihydro-2-methoxyethylimino-l,3-dimethylimidazole (C8H 15N30 , 10) is obtained from the reaction of methoxyethyl tosylate (7) and 2,3-dihydro-2-imino-l,3-dimethylimidazole (8) followed by deprotonation in good yield. 10 reacts with {(COD)RhCl}2 (COD = 1,5-cyclooctadiene) to give the imine complex (C8H 15N30)Rh(C0D)Cl (11), which is converted into the chelate complex [(C8H 15N30)Rh(C0D)]BF4 (12) on treatment with AgBF4. The imine complex (C8H 15N30) 2PdCl2 (13) is formed through the reaction of 10 with (PhCN)2PdCl2. The X-ray structures of 11, 13 and 2 C8H 15N30 • H2PdCl4 (15) are reported. R R 1 Rv -■ 
  Reference    Z. Naturforsch. 56b, 704—710 (2001); eingegangen am 28. März 2001 
  Published    2001 
  Keywords    Imidazoles, Rhodium, Palladium 
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 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-0704.pdf 
 Identifier    ZNB-2001-56b-0704 
 Volume    56 
2Author    Norbert Kuhn3, Riad Fawzi3, M. Anfred Steimann3, Jörg Wiethoff3, D. Ieter Bläserb, Roland BoesebRequires cookie*
 Title    Synthese und Struktur von 2-Imino-l,3-dimethylimidazolin [1] Synthesis and Structure of 2-Imino-l,3-dimethylimidazoline [1]  
 Abstract    Deprotonation of the 2-amino-1,3-dimethylimidazolium salt 5 (obtained through methyla-tion of 2-am ino-l-m ethylim idazole (4)) by KH gives 2-im ino-l,3-dim ethylim idazoline 6. The trimethylsilylimino compound 14 is formed on the reaction of 6 with chlorotrimethylsilane in the ratio 2:1. Further reaction with chlorotrimethylsilane gives the silylated aminoimidazo-lium salt 15. The X-ray structures o f 5 and 6 are reported. 
  Reference    Z. Naturforsch. 50b, 1779—1784 (1995); eingegangen am 23. Mai 1995 
  Published    1995 
  Keywords    Imidazole, Imine, X-Ray 
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 TEI-XML for    default:Reihe_B/50/ZNB-1995-50b-1779.pdf 
 Identifier    ZNB-1995-50b-1779 
 Volume    50 
3Author    Norbert Kuhna, Hans Bohnena, Gerald Henkelb, Jörg KreutzbergbRequires cookie*
 Title    5-Tetramethyl-2-methylenimidazoline -an Olefin with Ylidic Properties [ 1]  
 Abstract    A facile synthesis of l,3,4,5-tetramethyl-2-methylenimidazoline 5 (Im) starting from the pentamethylimidazolium ion (8) and KH is described. Boranes react with 5 to give the adducts ImBHi (11) and ImBF3 (18). With Mel and CH3C(0)C1 the imidazolium salts ImMe+ (19) and Im C (0)M e+ (20) are obtained. CS2 gives the zwitterionic compound ImCS2 (24) which is transformed into the cationic thiocarboxylic ester ImC(S)SCH2Cl+ on treatment with CH2C12. Reaction with chlorotrimethylsilane gives the imidazolium ion ImSiMe^ (26) which may be transferred into the disilylated imidazolium ion 28 via deprotonation and subsequent silylation, the silylated olefin 27 being the intermediate. Similarly, the cations ImSiR2Cl+ (29; R = Me, Ph) are obtained from 5 and the silanes R2SiCl2. The neutral adduct ImSnPh2Cl2 (32) is formed in the reaction of 5 with Ph2SnCl2. Iodine reacts with 5 to give the charge-transfer adduct Im l2 (35), which can be further transferred into the imidazolium salt Im l+I^ (36). verhilft Imidazolin-Derivaten des Typs 1 durch die Dominanz der Grenzstruktur 2 zu einer Ylid-artigen Bindungssituation. Als Belege können die Eigen­ schaften der 2-Chalkogenoimidazoline 1 (X = S [3,41, Se [4 -6 ], Te [4,7]) sowie des 2-Iminoimi-dazolins 3 (1 ,8 ] gelten. Die bekannte Polarisierung der olefinischen Dop­ pelbindung durch Substituenten mit +M-Charak-ter ist im Falle der Enamine [9] gut untersucht; durch Einbindung der Stickstoff-Atome des 1,1-Endiamins 4 in ein fünfgliedriges Ringsystem wird eine bemerkenswert hohe Basizität des Methylen­ kohlenstoffs erreicht [10]. Hierzu analog läßt sich durch Einbau eines olefinischen Kohlenstoffs in ein System zyklisch konjugierter 7 r-Elektronen gleich­ falls eine starke Polarisierung der olefinischen Dop­ pelbindung erreichen [11]. Die Kombination beider Effekte führt zum System des 2-Methylenimidaz-olins. Synthese und strukturelle Charakterisierung des Tetramethyl-Derivats 5 sind Gegenstand einer vorläufigen Mitteilung [12]. Über die Kupplungsre­ aktion von 5 zum Methinium-Kation 6 [13] sowie seine koordinationschemische Fixierung an Metall­ zentren (7) [14, 15] haben wir bereits an anderer Stelle berichtet. 
  Reference    Z. Naturforsch. 51b, 1267—1278 (1996); eingegangen am 8. März 1996 
  Published    1996 
  Keywords    Imidazoles, Olefins, X-Ray 
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 TEI-XML for    default:Reihe_B/51/ZNB-1996-51b-1267.pdf 
 Identifier    ZNB-1996-51b-1267 
 Volume    51 
4Author    M. Onoheteroarylborates [, Norbert Kuhn3, Heike Kotowski3, Dieter Bläserb, Roland BoesebRequires cookie*
 Title    Monoheteroarylborate [1]  
 Abstract    The heteroaryl borates Li[C4Me4NBH3] (6) and Na[C3H 3N2(BMe3)2]* 2 C4HgO (8) are ob­ tained by treatment of Li[C4Me4N] and Na[C3H3N2] with Me2S • BH3 and BMe3, respectively. The X-ray structure of [Na(C4H 80) 6][C3H 3N 2(BM e3)2] (10) is reported. 
  Reference    Z. Naturforsch. 52b, 351—354 (1997); eingegangen am 28. Oktober 1996 
  Published    1997 
  Keywords    Borates, Pyrroles, Imidazoles, X-Ray 
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 TEI-XML for    default:Reihe_B/52/ZNB-1997-52b-0351.pdf 
 Identifier    ZNB-1997-52b-0351 
 Volume    52 
5Author    N. Orbert Kuhn, Riad Faw, M. Anfred, Steim Ann, JörgW. Iethoff, HerrnRequires cookie*
 Title    Zur Reaktion von Derivaten des l,3-Dimethyl-2-iminoimidazolins mit CS2 [1]  
 Abstract    1,3-Dimethyl-2-iminoimidazoline (4, ImNH) reacts with CS2 to give the imidazolium salt [ImNH2][(ImNCS2)2H] (7) in which two dithioformimide fragments are linked by a hydrogen bridge. From the trimethylsilyl derivative ImNSiMe3 (11) and CS2 the adduct ImNSiMe3 • CS2 (12) is obtained which reacts with oxygen to give the disulfide (ImNCS2) (14). The X-ray structures of 7 and 14 were determined. 
  Reference    Z. Naturforsch. 52b, 609—614 (1997); eingegangen am 19. Februar 1997 
  Published    1997 
  Keywords    Imidazoles, Carbon Disulfide, X-Ray 
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 TEI-XML for    default:Reihe_B/52/ZNB-1997-52b-0609.pdf 
 Identifier    ZNB-1997-52b-0609 
 Volume    52 
6Author    Norbert Kuhna, Stefan Fuchs3, Rolf Minkwitzb, Thorsten Berendsb, Herrn Professor, DrH P FritzRequires cookie*
 Title    Collidinium-und Imidazolium-Salze Fluor-haltiger Anionen  
 Abstract    Die Kristall­ struktur von [CollH]2 [AsF6][As2 Fu ] (Coli = 2,4,6-Trimethylpyridin) Collidinium and Imidazolium Salts of Fluorine-Containing Anions. The Crystal Structure of [CollH]2[AsF6][As2Fl l ] (Coll = 2,4,6-Trimethylpyridine) From s-Collidine (1, Coll) and aqueous HF compounds of the composition Coll • n HF (n = 1 -2) are formed which are transformed to [CollH]+ [HF2]~ (2) by sublimation. [CollH]2[AsF6][As2F] J (3) is obtained from 1 and the superacid system HF/AsF5. 2 reacts with 2,3-dihydro-l,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (4, Im) to give the imidazo­ lium salt [ImH]+ [HF2]~ (5). Hydrogen bonds in the crystal structure of [CollH]2[AsF6][As2Fn ] (3) are discussed. 
  Reference    Z. Naturforsch. 56b, 626—629 (2001); eingegangen am 3. Mai 2001 
  Published    2001 
  Keywords    Hydrogen Fluoride, Imidazoles, Pyridines 
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 TEI-XML for    default:Reihe_B/56/ZNB-2001-56b-0626.pdf 
 Identifier    ZNB-2001-56b-0626 
 Volume    56 
7Author    Nobuo Nakamura, Hirotsugo Masui, Takahiro UedaRequires cookie*
 Title    Effect of Intermolecular Hydrogen Bonding on the Nuclear Quadrupole Interaction in Imidazole and its Derivatives as Studied by ab initio Molecular Orbital Calculations  
 Abstract    Ab initio Hartree-Fock molecular orbital calculations were applied to the crystalline imidazole and its derivatives in order to examine systematically the effect of possible N-H---N type hydrogen bond-ing on the nuclear quadrupole interaction parameters in these materials. The nitrogen quadrupole coupling constant (QCC) and the asymmetry parameter (r?) of the electric field gradient (EFG) were found to depend strongly on the size of the molecular clusters, from single molecule, to dimer, trimer and to the infinite molecular chain, i.e., crystalline state, implying that the intermolecular N-H -N hydrogen bond affects significantly the electronic structure of imidazole molecule. A certain correla-tion between the QCC of l4 N and the N-H bond distance R was also found and interpreted on the basis of the molecular orbital theory. However, we found that the value of the calculated EFG at the hy-drogen position of the N-H group, or the corresponding QCC value of 2 H, increases drastically as /C* when R is shorter than about 0.1 nm, due probably to the inapplicability of the Gaussian basis sets to the very short chemical bond as revealed in the actual imidazole derivatives. We suggested that the ob-served N-H distances in imidazole derivatives should be re-examined. 
  Reference    Z. Naturforsch. 55a, 315—322 (2000); received August 26 1999 
  Published    2000 
  Keywords    Hydrogen Bond, Nuclear Quadrupole Interaction, Molecular Orbital, Imidazole 
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 TEI-XML for    default:Reihe_A/55/ZNA-2000-55a-0315.pdf 
 Identifier    ZNA-2000-55a-0315 
 Volume    55 
8Author    Norbert Kuhn3, Joanna Fahl3, Roland Boeseb, Gerald HenkelcRequires cookie*
 Title    Zur Reaktion von 2,3-Dihydroimidazol-2-ylidenen mit Pentafluorpyridin: Carbene als Reaktionspartner in der nucleophilen aromatischen Substitution [1] On the Reaction of 2,3-Dihydroimidazol-2-ylidenes with Pentafluoropyridine: Carbenes as Reactants in Nucleophilic Aromatic Substitution [1]  
 Abstract    The 2,3-dihydro-l,3,4,5-tetraalkylimidazol-2-ylidenes 3 (R = Me, i'so-Pr) react immediately with pentafluoropyridine to form the 2-tetrafluoropyridylimidazolium salts 4 in good yields. In contrast with the tetramethyl derivative 4a, alkyl fluoride is eliminated from the isopropyl salt 4b to give 1 -isopropyl-4,5-dimethyl-2-tetrafluoropyridylimidazole, which dimerises via hydrogen bridges in the solid state (7). The X-ray structures of l,3-diisopropyl-4,5-dimethyl-2-tetrafluoropyridylimidazolium chloride (5) and 7 are reported. 
  Reference    Z. Naturforsch. 53b, 881—886 (1998); eingegangen am 9. April 1998 
  Published    1998 
  Keywords    Carbenes, Imidazoles, Pyridines, Nucleophilic Aromatic Substitution, Hydrogen Bonds 
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 TEI-XML for    default:Reihe_B/53/ZNB-1998-53b-0881.pdf 
 Identifier    ZNB-1998-53b-0881 
 Volume    53 
9Author    N. Orbert, K. Uhn, M. Anfred, Steim Ann, Gerd Weyers, HerrnRequires cookie*
 Title    Synthese und Eigenschaften von l,3-Diisopropyl-4,5-dimethylimidazolium- 2-car boxy lat. Ein stabiles Carben-Addukt des Kohlendioxids [1]  
 Abstract    The reaction of 2,3-dihydro-l,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (5) with C 0 2 gives the imidazolium-2-carboxylate 6 . The compound can be transformed into the salts of its corresponding Broenstedt acid 8 . The cationic acid chloride 10a is obtained from 6 and thionyl chloride. Chemical properties and spectroscopic data indicate 6 to be less basic than its anionic counterparts, e. g. PhC02 . The X-ray structure of 
  Reference    Z. Naturforsch. 54b, 427—433 (1999); eingegangen am 27. November 1998 
  Published    1999 
  Keywords    Carbenes, Imidazoles, Carboxylic Acids, X-Ray Data 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0427.pdf 
 Identifier    ZNB-1999-54b-0427 
 Volume    54 
10Author    Norbert Kuhn, Manfred Steimann3, Gerd Weyers3, Gerald Henkelh, HerrnRequires cookie*
 Title    l,3-DHSopropyl-4,5-dimethylimidazolium-2-N,N'-diisopropylamidinat, ein neuartiges Retain [1] 1,3-Diisopropyl-4,5-dimethylimidazolium-2-N,N'-diisopropylamidinate, a Novel Betaine [1]  
 Abstract    The imidazolium-2-amidinate 6 is obtained from the reaction of 2,3-dihydro-1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (4) with diisopropylcarbodiimide (5) as stable solid. Overcrow­ ding causes a lowered symmetry of the amidinate fragment indicated both by structural and NMR data. The strongly basic properties of 6 allow facile protonation with HC1 to the cationic amidine derivatives 7 and 8 . The ketoamidine 10 is formed by a ring opening reaction of 6 with water. I he X-ray structures of 6 and 10 are reported 
  Reference    Z. Naturforsch. 54b, 434—440 (1999); eingegangen am 21. Dezember 1998 
  Published    1999 
  Keywords    Amidines, Carbenes, Carbon Diimides, Imidazoles, X-Ray Data 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-0434.pdf 
 Identifier    ZNB-1999-54b-0434 
 Volume    54 
11Author    Norbert Kuhn, Elke Niquet, Manfred Steimann, Isabel WalkerRequires cookie*
 Title    Methoxyalky 1-funktionalisierte 2,3-Dihy droimidazol-2-ylidene [ 1 ] Methoxyalkyl Functionalized 2,3-Dihydroimidazol-2-ylidenes [1]  
 Abstract    The 2,3-dihydro-l,3-di(methoxyalkyl)imidazol-2-ylidenes are obtained from the correspon­ ding cyclic thioureas and potassium. With CS2, the imidazolium dithiocarboxylates are formed. The results of X-ray structure determinations of two of these products are reported. 
  Reference    Z. Naturforsch. 54b, 1181—1187 (1999); eingegangen am 8. Juni 1999 
  Published    1999 
  Keywords    Carbenes, Imidazoles, Dithiocarboxylates, X-Ray Data 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-1181.pdf 
 Identifier    ZNB-1999-54b-1181 
 Volume    54 
12Author    G., R. Ia, N. IeRequires cookie*
 Title    Investigation of Inductive Effects on the Transphosphorylation Reaction of Spin-Labeled Phosphoryl Imidazolides, Part  
 Abstract    Spin-labeled phosphoryl imidazolides 3, 6 , and 7 were prepared and compared to the unsubstituted compound 1 in reactivity towards hydroxy and amino compounds. The transphorphorylation reaction of compounds 3 and 6 was slower than that of 1. The reaction of compound 6 was selective towards amines since no reaction occurred with hydroxy compounds. The reaction of compounds 7 was slow with hydroxy compounds and rapid with amines at room temperature. The transphorphorylation reaction of 1 was rapid with both hydroxy and amino compounds at 50-55 °C. 
  Reference    (Z. Naturforsch. 32b, 1182—1188 [1977]; received July 4 1977) 
  Published    1977 
  Keywords    Spin-Labeling, Nitroxyl, Imidazoles, Spin-Labeled Phosphates, Spin-Labeled Phosphoroamidates 
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 TEI-XML for    default:Reihe_B/32/ZNB-1977-32b-1182.pdf 
 Identifier    ZNB-1977-32b-1182 
 Volume    32 
13Author    George Sosnovsky, Maria KoniecznyRequires cookie*
 Title    Investigation of Inductive Effects on the Transphosphorylation Reaction of Spin-Labeled Phosphoryl Imidazolides, Part II  
 Abstract    The effect of electron-releasing and electron-withdrawing groups in the benzene ring of imidazolide 4 (R 1 = CH3, Cl, NO2) was studied. The 
  Reference    Z. Naturforsch. 33b, 797—804 (1978); received March 17 1978 
  Published    1978 
  Keywords    Spin-labeled Phosphates, Spin-labeled Phosphoroamidates, Nitroxyl Radical, Imidazole, Inductive Effects 
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 TEI-XML for    default:Reihe_B/33/ZNB-1978-33b-0797.pdf 
 Identifier    ZNB-1978-33b-0797 
 Volume    33 
14Author    G. Erhard, N. Schrauzer, PaulA. Doemeny, JohnG. PalmerRequires cookie*
 Title    The Chemical Evolution o f a Nitrogenase Model, XXII. Reduction of Acetylene with Catalysts Derived from Molybdate, Homocitric Acid and N-M ethylimidazole and a Proposal Concerning the Active Site of Functional Azotobacter Nitrogenases  
 Abstract    Based on model experiments it is suggested that the reduction o f substrates by nitrogenase occurs at a m ononuclear site containing molybdenum, homocitrate and the imidazole com ponent of his-442 o f the apoenzyme, generated from the FeMo-co by a reversible dissociation of the Fe7S8 unit from the M oFe7S8 cluster in a redox-linked process. 
  Reference    Z. Naturforsch. 48b, 1295—1298 (1993); received May 14 1993 
  Published    1993 
  Keywords    Nitrogenase, Acetylene Reduction, M olybdenum-Catalyzed, Homocitric Acid, Histidine, Imidazole 
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 TEI-XML for    default:Reihe_B/48/ZNB-1993-48b-1295_n.pdf 
 Identifier    ZNB-1993-48b-1295_n 
 Volume    48 
15Author    Takahiro Ueda, Shigenori Nagatomo, Hirotsugu Masui, Nobuo Nakamura, Shigenobu HayashiRequires cookie*
 Title    Hydrogen Bonds in Crystalline Imidazoles Studied by 15 N NMR and ab initio MO Calculations  
 Abstract    Intermolecular hydrogen bonds of the type N-H...N in crystals of imidazole and its 4-substituted and 4,5-disubstituted derivatives were studied by 15 N CP/MAS NMR and an ab initio molecular orbital (MO) calculation. In the 15 N CP/MAS NMR spectrum of each of the imidazole derivatives, two peaks due to the two different functional groups, >NH and =N-, were observed. The value of the I 5 N isotrop-ic chemical shift for each nitrogen atom depends on both the length of the intermolecular hydrogen bond and the kind of the substituent or substituents. It was found that the difference between the experimen-tal chemical shifts of >NH and =N-varies predominantly with the hydrogen bond length but does not show any systematic dependence on the kind of substituent. The ab initio MO calculations suggest that the hydrogen bond formation influences the 15 N isotropic chemical shift predominantly, and that the difference between the 15 N isotropic chemical shift of >NH and =N-varies linearly with the hydrogen bond length. 
  Reference    Z. Naturforsch. 54a, 437—442 (1999); received March 31 1999 
  Published    1999 
  Keywords    15 N CP/MAS NMR, Imidazoles, Hydrogen Bond, 15 N Chemical Shift, ab initio MO Calculation 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0437.pdf 
 Identifier    ZNA-1999-54a-0437 
 Volume    54 
16Author    Detlef GeffRequires cookie*
 Title    Imidazole Catalyzed Transformation of 2-Arylmethylperhydro-l,5,2-dioxazine- 3,6-diones into 4-Oxazolidinones  
  Reference    Z. Naturforsch. 38b, 531—534 (1983); eingegangen am 23. November 1982 
  Published    1983 
  Keywords    2 -Ary lmethy lperhydro -1, 5, 2 -dioxazine -3, 6-diones, Imidazole, Thermolysis, 4-Oxazolidinones, Glyoxylamides 
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 TEI-XML for    default:Reihe_B/38/ZNB-1983-38b-0531_n.pdf 
 Identifier    ZNB-1983-38b-0531_n 
 Volume    38